The Things We Make by Bill Hammack

Author:Bill Hammack
Language: eng
Format: epub
Publisher: Sourcebooks

The second method historically didn’t fare better. The earliest recorded version of the steam paddle wheel device is from 1629, when Giovanni Branca, an Italian engineer, proposed a giant boiler, shaped like a human head, that blasted a jet of steam onto a paddle wheel. When engineers built devices like Branca’s, not only did the paddle wheel spin so fast that it blew apart, the expelled steam cut through the metal blades. It seemed that inherent in the direct transfer of steam power to circular motion was an impasse between the force of steam necessary to do useful work and the ability of a machine’s materials to withstand the relentless power of that force.

To overcome this no-win scenario, then, Parsons knew he must slow the flow rate of steam to tame the rotations and, as he put it, “avoid the well-known cutting action on metal of steam at high velocity.”11 To this problem, Parsons applied what his wife called his “outstanding feature,” his power of concentration.12 “Nothing disturbed him when he was absorbed in a problem,” she said. “No noises, no discomfort, no time and no meals—he was perfectly oblivious to them all.” Indeed, Parsons, when on the scent of a solution, worked twenty-four, even thirty-six hours straight. Late at night, he sat in his study, a white-sulfur cockatoo at his side, to whom he absentmindedly fed sugar lumps. And during the day, when in this state, he walked around his machine shop with a glassy gaze. Once, he was so distracted that he stepped into a bucket of lubricating oil; another time, he stepped backward off a three-foot-high platform, struck the edge of a machine, and nearly broke his ribs. This deep thought, though, led him to his breakthrough design: Parsons realized that the high velocities that tore apart early machines occurred because the high-pressure steam was vented to the atmosphere, which causes the steam to rush out at hurricane speeds. He reasoned that if he could drop the pressure through a series of contained steps—so no drop was too large—he could reduce the flow rate of the steam yet eventually extract all its energy.

Although his idea was straightforward in principle, Parsons described the practical problems of executing his design as of “almost infinite complexity”13—the number of steps he should use to slowly drop the steam pressure, the speeds of rotation caused by the steam’s pressure, and the question of whether the steam’s velocity was low enough to avoid cutting steel. To find his way in this “infinite complexity,” Parsons turned to what he had referred to as the “data of the physicists.”14 His engineering solution would be impossible without the help of science.

In the thirty years before Parsons’s work, the field of thermodynamics—the study of energy and its transformations—blossomed thanks to two scientists who contrasted greatly in their work and their personalities and who are forgotten to all except the most dedicated historians of science. The first is the French scientist Henri-Victor Regnault, a man so famous in

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